Kentucky Bluegrass
Poa pratensis · Cool-season, Perennial, C3 grass
AI-generated identification · may be incorrect
Grass Category
Lawn/Turf Grass, Sports Turf
Hardiness Zones
Thrives in USDA Hardiness Zones 3 through 7, tolerating freezing northern winters very well but struggling with extreme, humid summer heat unless irrigated.
Grass Family
Poaceae, subfamily Pooideae, tribe Poeae
Variety / Cultivar
Common blend (such as 'Midnight' or 'Compact Midnight' types often used in northern lawns)
About This Grass
Forms a dense, high-quality turf with medium-fine texture and a rich dark green to blue-green color. Mown height typically ranges from 1.5 to 2.5 inches, while unmowed seed heads can reach 18 to 24 inches. Produces open, pyramidal panicle seed heads at maturity in late spring.
Blade Characteristics
Blades are medium-narrow (2-4mm wide), flat to folded in the bud with distinctive boat-shaped tips and parallel sides. Features prominent parallel veins creating a railroad-track appearance. Ligules are short and membranous, with no auricles.
Root System
Moderate depth (6-12 inches) with an extensive fibrous and rhizomatous root network that creates a very tough, dense sod. Tends to build moderate thatch over time and establishes somewhat slowly from seed.
Growing Information
Origin Region
Native to Europe, northern Asia, and parts of the mountains in North America; widely naturalized and cultivated across cool-temperate regions worldwide.
Growth Habit
Rhizomatous, spreading underground via aggressive underground stems to form a dense, uniform turf mat.
Sunlight & Water Needs
Requires full sun (minimum 6-8 hours of direct sunlight) for optimal growth, though some shade-tolerant cultivars exist. High water needs during hot, dry periods to maintain color, and enters summer dormancy (turning brown) if drought is prolonged.
Mowing & Maintenance
Mow at 2 to 3 inches with sharp blades. Requires a medium-high maintenance level, needing 3 to 4 lbs of nitrogen per 1,000 sq ft annually, regular irrigation, annual aeration, and occasional dethatching.
Special Characteristics
Excellent traffic tolerance and self-repairing capability via rhizomes. Moderate shade tolerance, good disease resistance against many common turf fungi, and excellent cold winter survival.
Ecological Information
Introduced species in North America widely used for erosion control, residential lawns, and sports fields. Provides modest ground cover for small wildlife and is frequently blended with Perennial Ryegrass and Fine Fescue.